Test procedure for fluorocarbon gross leak test requires the device be inserted into the combination vacuum/pressure vessel and reduce the ambient pressure to less than five tarr for 30 minutes. Then without breaking vacuum, a sufficient quantity of leak detecting fluid to cover the device shall be drawn into the vacuum/pressure vessel through a transfer tube from a container of leak detecting fluid. For devices with an internal cavity volume of 0.1 cc or less, the pressure in the vessel shall be increased and maintained at 75 psig for a duration of one hour minimum. For devices with an internal cavity volume in excess of 0.1 cc a minimum pressure of 30 psig shall be applied and maintained for a duration of two hours minimum.
The pressure is released and the device shall be removed from the pressure vessel and retained immersed in a bath containing the leak detecting fluid. The device is removed from the leak detecting fluid and dried in air for three minutes. The device shall be immersed in the leak indicator fluid, which is maintained at 125.degree..+-.5.degree. C. A device shall be observed, from the instant of immersion until 30 seconds after immersion, for bubbles as to their occurrences and source, unless bubbles occur earlier. Device failure criteria for this test shall be the observation from a package of definite system of bubbles, more than two large bubbles or an attached bubble that grows in size from the instant of immersion for 30 seconds unless failure occurs earlier. Minimum time for testing 25 units will be one hour, 35 minutes. Maximum time will be two hours, 35 minutes for testing 25 units.
The pneumatic gross leak tester will test 25 devices in 15 minutes. Devices with an internal cavity volume greater than, or less than, 0.1 cc can be tested at this rate.
The pneumatic gross leak tester will detect pressure differences between a hermatically sealed micro-electronic device and a gross leak micro-electronic device. The micro-electronic circuit is sealed in a metallic package. The lid is electrostatic welded to the base of the package. A gross leak is usually found between the lid and the base of the package. When a gross leak is detected, the package can be welded again, and then tested again for a gross leak.